OBJECTIVES: 1. Recheck and improve our previous method of preparation of human alpha 1 inhibitor with respect to possible contamination with orosomucoid but without decreasing the scale. Investigate the purified human alpha 1 in terms of repetitious domains for trypsin (1 or 2), chymotrypsin and elastase. Particularly compare the action of human alpha 1 agains elastases from different sources. 2. Prepare sufficient amount of virgin bovine secretory isoinhibitors for x-ray diffraction study. Prepare at least one isoinhibitor in a modified form to compare the change in structure responsible for the exposure of the "temporary" bond. 3. Inhibitors of swine colostrum. Separate the high molecular inhibitor from the low molecular, separate the latter into isoinhibitors using mild conditions. Characterize the high molecular inhibitor in terms of similarity with blood alpha 1, or in terms of similarity of a domain with the low molecular isoinhibitors.